The prior art has included numerous surgically implantable prosthetic valves which may be utilized to replace malfunctioning heart valves, such as the aortic valve and the mitral valve. Some of the prosthetic heart valves of the prior art are "mechanical" valves of non-biological origin. Others are "biological" valves wherein all or a portion of the valve consists of harvested mammalian (e.g., porcine) tissue which has been preserved by way of a chemical fixation process.
Although surgically implantable prosthetic heart valves have become widely used in clinical practice, their implantation involves a major cardiothoracic surgical procedure wherein the patient must be placed on full cardiopulmonary bypass for a significant period of time. As a result, patients who have severe complications of their valvular disease or who are otherwise severely ill or elderly may be unable to undergo the rigors of such major cardiothoracic surgical procedure and are, thus, unable to receive the benefits of a surgically implanted prosthetic cardiovascular valve.
A number of prior investigators have proposed various "collapsible" cardiovascular valves and other cardiovascular apparatus (e.g., embolus traps) which may be collapsed and inserted into the mammalian vasculature through the lumen of a tubular catheter or introducer. Examples of collapsible cardiovascular valves and related apparatus are found in U.S. Pat. Nos. 3,671,979; 4,056,854; 4,592,340; 4,727,873; 4,817,600; 4,960,424; 4,994,077; 5,163,953; and 5,207,695, as well as the following foreign patents and/or patent publications WO91/17720; DT 2700-531 and WO93/01768.
Although various collapsible, catheter deployable, heart valves and/or other cardiovascular apparatus may have been proposed in the prior art, there remains a need for further refinement and development of such devices so as to arrive at a clinically useful prosthetic cardiovascular valve which may be implanted, through the lumen of a cardiovascular catheter, without the need for major cardiothoracic surgery.